I already have my corys in it...since their 5g tanks werent cycled anyways I figured what the heck...it will speed things up seeing as how the girls are supposed to be here by the end of the week :S
I have never cycled before...and probably should have told the pet store to wait another week before ordering the girls.

I am in the same situation! My girls should be here this week as well and I don't think my tank will be done cycling yet. But, the way I look at it, I need to quarantine them anyway for a week or two to make sure they are all healthy before putting them together. So just look at it that way!

Just go out and buy a couple of clean, new tupperware containers. Or hate to say it, but you could keep them in their cups if you really can't get anythign bigger. Just make sure to change the water everyday.
Trust me, you need to quarantine! So many problems will be avoided if you do..

Sorority tanks usually end up being more about the safety of the fish than looks, haha, it's hard to avoid the stuffed look you'll end up with. You should really try to find a way to fill in the top section more--all bettas must go up to the surface to breathe and this is also were they go to eat, so squabbling near the surface is inevitable. Floating plants should help with this. You should try ordering online, often the prices are a lot better and you have a much nicer selection. You might try Big Al's online: http://www.bigalsonline.ca/BigAlsCA/...wType=Category

Also, you might want to look carefully at the skull ornament--I've seen a fish get stuck in and mangled by a very similar (if not the same) ornament. I recommend stuffing the smaller holes with plant matter, filter floss, or filling it in with aquarium silicone. Injuries from getting stuck can be really nasty, and during a moment of fear a fish can dart into some very sticky situations.